[Note: microRNAs (miRNAs) are biological regulators of cell function [see video]. Aberrant expression of microRNAs has been implicated in numerous disease states, with the result that investigations to identify, understand and potentially manipulate them represent a cutting-edge field of research.]

Background: Immune dysfunction associated with a disease often has a molecular basis.

A novel group of molecules known as microRNAs (miRNAs) have been associated with suppression of translational processes involved in cellular development and proliferation, protein secretion, apoptosis, immune function and inflammatory processes.

MicroRNAs may be implicated in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), where immune function is impaired.

The objective of this study was to determine the association between miRNAs in cytotoxic cells and CFS/ME. ['Cytotoxic' denotes 'cell-killing'.]